The present invention relates to a device for controlling fluid movements, especially a device capable of being used in ink jet printers.
In the field of ink jet printing, it is important to control the quantity of ink to be ejected in order to obtain optimum print quality. In the case of color printing, the print quality also depends on the color rendition obtained. Generally, ink jet color printers have reservoirs with each containing ink with a defined color, and each color of ink is ejected through a nozzle in the ink jet head. Usually, the inks used are inks with the colors yellow, magenta, cyan and black. The printing of a series of dots of yellow, magenta, cyan and black ink is controlled by a dithering technique that enables the different colored dots to be arranged so as to represent any color. U.S. Pat. No. 5,612,725 as an example, discloses a method for recording characters on a recording medium with specific recording heads, wherein devices including piezoelectric elements that generate a change of pressure allow the ink to be jetted out of nozzles in ink drops. The invention disclosed in U.S. Pat. No. 5,612,725 is an ink-jet recording head whose nozzles and ink flow channels can readily be formed and thus mass produced and which uses inexpensive glass and plastic plates. Components of the ink-jet recording head are collected together by a thermal fusion bonding method which improves the quality of the assembly. Moreover, the inner faces of the through-hole and the intermediate nozzle are made hydrophilic, whereas the inner and open faces of the terminal nozzle are made water-repellent or hydrophobic. The state of faces of the components are permanently either hydrophilic or hydrophobic; while the state of a given element cannot be changed from hydrophilic to hydrophobic or vice-versa. The problem with such a printing technique is that the print dots are visible.
An object of the present invention is to provide for a device that enables the movement of fluids to be controlled with accuracy, in particular to move fluid quantities defined with precision.
A further object of the present invention is to provide for a device that enables the control of several fluids in order to obtain mixtures of these fluids defined with precision.
The invention relates to a device for controlling fluid movements that comprises:
a) a fluid guiding element for guiding fluids;
b) at least one fluid moving element for moving fluids, with the at least one fluid moving element comprising polymers having hydrophilic and hydrophobic properties corresponding to two different hydrophilic or hydrophobic states of the polymers, and the properties being selected under an action of an external force; and
c) at least one actuating unit which generates the external force, with the at least one fluid moving element comprising a plurality of polymer elements whose hydrophilic and hydrophobic properties are selected. The polymer elements are arranged along the fluid guiding element and the polymer elements are actuated in succession to switch from the hydrophilic state to the hydrophobic state or vice-versa, in order to gradually move a quantity of fluid along the fluid guiding element.
The present invention also relates to a device for controlling fluid movement that comprises at least one channel which guides fluid; a plurality of polymer elements arranged along the at least one channel, with the plurality of polymer elements having hydrophilic and hydrophobic properties and being switchable between hydrophilic and hydrophobic states upon an action of an external force; and at least one actuating unit which provides the external force to change a state of the polymer element and cause a movement of the fluid in the at least one channel.
The present invention also relates to a method of moving fluid which comprises the steps of: supplying fluid to at least one guide channel, with the at least one guide channel having a plurality of polymer elements arranged there along, and the plurality of polymer elements having hydrophilic and hydrophobic properties and being switchable between hydrophilic and hydrophobic states; and moving the fluid in the at least one channel by applying an external force to at least one of the polymer elements to change a state of the at least one of the polymer elements.
The present invention further relates to a device for controlling fluid movement which comprises: a plurality of polymer elements arranged on a flat surface, with the plurality of polymer elements having hydrophilic and hydrophobic properties and being switchable between hydrophilic and hydrophobic states upon an action of an external force; and at least one actuating unit which provides the external force to change a state of the polymer element and cause a movement of the fluid on the flat surface.
The present invention also relates to a method of moving fluid which comprises the steps of: supplying fluid to a flat surface, with the flat surface having a plurality of polymer elements arranged thereon, and the plurality of polymer elements having hydrophilic and hydrophobic properties and being switchable between hydrophilic and hydrophobic states; and moving the fluid on the flat surface by applying an external force to at least one of the polymer elements to change a state of the at least one of the polymer elements.